class mediator_interface_of_filesystem :
    def create_file ( self , name , contents ) :
        self . _modules . filesystem . create_file ( name , contents )
    def delete_file ( self , name ) :
        self . _modules . filesystem . delete_file ( name )
    def list_files_request ( self ) :
        self . _modules . filesystem . list_files_request ( )
    def read_file_request ( self , name ) :
        self . _modules . filesystem . read_file_request ( name )
